Temperature Gradient in Multi-Diffusion Couples for Experimental Determination of Thermodynamic Response from Systems with Numerous Components

几十年来一直使用扩散偶来确定热力学数据，从而构建相图。通过使用多扩散偶，可以分析4段加外壳材料。这允许分析多达9个二元和6个三元系统。该提案中的新方法是引入温度梯度。从而得到了不同高度试样的等温截面。这导致了一个非常有效的确定扩散过程中一般和扩散控制系统中的相变与几个组成部分在一个广泛的组成和温度范围。目标材料在开始是铬基合金与Cr-Si-X-Y组成。对于附加元素X和Y，存在几个有趣的选项。迄今为止用作外壳材料的元素Ni由于其低熔化温度而被淘汰。因此，必须确定新的外壳材料。下一步将是调整现有的冷壁真空炉，在温度梯度中对扩散倍数进行热处理。最后，将扩散倍数切割成不同的高度（对应于不同的退火温度）并进行分析。这使得一个非常有效的方法来确定等温切割的相图和扩散机制的系统中的几个组件。

Diffusion couples are used since several decades to determine thermodynamic data and thereby to construct phase diagrams. By using multi-diffusion couples 4 segments plus enclosure material can be analyzed. This allows to analyze up to 9 binary and 6 tertiary systems. The new approach in this proposal is to incorporates a temperature gradient. Thereby we obtain different isothermal sections in different heights of the sample. This leads to a very effective determination of diffusion processes in general and to diffusion controlled phase changes in systems with several components over a wide compositional and temperature range.Target material at the beginning are chromium based alloys with Cr-Si-X-Y composition. Several interesting options exist for the additional elements X and Y. The element Ni, so far used as enclosure material drops out because of its low melting temperature. Therefore, a new enclosure material has to be determined. The next step will be to adjust an already existnt cold-wall vacuum furnace for heat treating the diffusion multiples in a temperature gradient. Finally, the diffusion multiple will be cut in different heights (corresponding to different annealing temperatures) and analyzed. This allows a very efficient way to determine isothermal cuts of phase diagrams and diffusion mechanisms in systems with several components.